// This optional code is used to register a service worker.
// register() is not called by default.
// This lets the app load faster on subsequent visits in production, and gives
// it offline capabilities. However, it also means that developers (and users)
// will only see deployed updates on subsequent visits to a page, after all the
// existing tabs open on the page have been closed, since previously cached
// resources are updated in the background.
// To learn more about the benefits of this model and instructions on how to
// opt-in, read http://bit.ly/CRA-PWA
var isLocalhost = Boolean(window.location.hostname === 'localhost' || // [::1] is the IPv6 localhost address.
window.location.hostname === '[::1]' || // 127.0.0.1/8 is considered localhost for IPv4.
window.location.hostname.match(/^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/));
export function register(config) {
  var PUBLIC_URL = process.env.PUBLIC_URL;

  if (process.env.NODE_ENV === 'production' && 'serviceWorker' in navigator) {
    // The URL constructor is available in all browsers that support SW.
    var publicUrl = new URL(PUBLIC_URL, window.location.href);

    if (publicUrl.origin !== window.location.origin) {
      // Our service worker won't work if PUBLIC_URL is on a different origin
      // from what our page is served on. This might happen if a CDN is used to
      // serve assets; see https://github.com/facebook/create-react-app/issues/2374
      return;
    }

    window.addEventListener('load', function () {
      var swUrl = "".concat(PUBLIC_URL, "/service-worker.js");

      if (isLocalhost) {
        // This is running on localhost. Let's check if a service worker still exists or not.
        checkValidServiceWorker(swUrl, config); // Add some additional logging to localhost, pointing developers to the
        // service worker/PWA documentation.

        navigator.serviceWorker.ready.then(function () {
          console.log('This web app is being served cache-first by a service ' + 'worker. To learn more, visit http://bit.ly/CRA-PWA');
        });
      } else {
        // Is not localhost. Just register service worker
        registerValidSW(swUrl, config);
      }
    });
  }
}

function registerValidSW(swUrl, config) {
  navigator.serviceWorker.register(swUrl).then(function (registration) {
    var reg = registration;

    reg.onupdatefound = function () {
      var installingWorker = reg.installing;

      if (installingWorker == null) {
        return;
      }

      installingWorker.onstatechange = function () {
        if (installingWorker.state === 'installed') {
          if (navigator.serviceWorker.controller) {
            // At this point, the updated precached content has been fetched,
            // but the previous service worker will still serve the older
            // content until all client tabs are closed.
            console.log('New content is available and will be used when all ' + 'tabs for this page are closed. See http://bit.ly/CRA-PWA.'); // Execute callback

            if (config && config.onUpdate) {
              config.onUpdate(reg);
            }
          } else {
            // At this point, everything has been precached.
            // It's the perfect time to display a
            // "Content is cached for offline use." message.
            console.log('Content is cached for offline use.'); // Execute callback

            if (config && config.onSuccess) {
              config.onSuccess(reg);
            }
          }
        }
      };
    };
  }).catch(function (error) {
    console.error('Error during service worker registration:', error);
  });
}

function checkValidServiceWorker(swUrl, config) {
  // Check if the service worker can be found. If it can't reload the page.
  fetch(swUrl).then(function (response) {
    // Ensure service worker exists, and that we really are getting a JS file.
    var contentType = response.headers.get('content-type');

    if (response.status === 404 || contentType != null && contentType.indexOf('javascript') === -1) {
      // No service worker found. Probably a different app. Reload the page.
      navigator.serviceWorker.ready.then(function (registration) {
        registration.unregister().then(function () {
          window.location.reload();
        });
      });
    } else {
      // Service worker found. Proceed as normal.
      registerValidSW(swUrl, config);
    }
  }).catch(function () {
    console.log('No internet connection found. App is running in offline mode.');
  });
}

export function unregister() {
  if ('serviceWorker' in navigator) {
    navigator.serviceWorker.ready.then(function (registration) {
      registration.unregister();
    });
  }
}